California Oakworm

The California oakworm is one species of caterpillar that feeds on oak trees.

Which species of oak tree are most commonly at risk?

Damage is very common on the coast live oak. Most often seen in the San Francisco Bay area, infestations are unpredictable from year to year.

What is the life cycle of oakworms?

During the fall, females lay eggs that hatch and overwinter into pupae until late Spring. Overwintering typically does not occur on deciduous oaks, which lose their leaves in the fall season. These oakworm pupae emerge as moths mid-summer. You can often see them flying around the trees.

Females also lay eggs that hatch and feed from mid-summer to early-fall and emerge a

What damage will I see on my oak trees?

The young larvae skeletonize the leaves while the more mature larvae eat the entire leaf.

Management and treatment solutions?

Inspect your trees regularly for oakworms during the active seasons. Your arborist can recommend the proper treatment option for your landscape. Fertilization of trees showing stress from defoliation is also recommended.